Sintering behavior, microstructure and microwave dielectric properties of Li2+xTiO3 (0 ≤ x ≤ 0.2)

Sintering behavior, microstructure and microwave dielectric properties of Li2+xTiO3 (0 ≤ x ≤ 0.2) ceramics have been studied by X-ray diffraction (XRD), scan electron microscopy (SEM), Raman spectra, dilatometery and microwave resonant measurement in this research. Homogeneous non-stoichiometric composition with rock salt structure existed for Li2+xTiO3 (0 ≤ x ≤ 0.2) ceramics. The sintering temperature was successfully reduced and highly densified sample could be obtained with appropriate excessive amount of lithium (x = 0.08). A transient reactive liquid phase sintering mechanism was proposed. The preferred orientation of grain growth and micro-cracks existed in the Li2TiO3 (x = 0) sample disappeared in the lithium excessive samples with x ≥ 0.08. The microwave dielectric properties varied significantly with the excessive amount of lithium. Optimized microwave dielectric properties were obtained for the x = 0.08 composition: ɛr = 24.6, Q × f = 66,000 GHz, and τf = 22.1 ppm/°C.